// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2009-2010 Gael Guennebaud <gael.guennebaud@inria.fr>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#include "common.h"

// computes the sum of magnitudes of all vector elements or, for a complex vector x, the sum
// res = |Rex1| + |Imx1| + |Rex2| + |Imx2| + ... + |Rexn| + |Imxn|, where x is a vector of order n
RealScalar
EIGEN_BLAS_FUNC(asum)(int* n, RealScalar* px, int* incx)
{
	//   std::cerr << "_asum " << *n << " " << *incx << "\n";

	Scalar* x = reinterpret_cast<Scalar*>(px);

	if (*n <= 0)
		return 0;

	if (*incx == 1)
		return make_vector(x, *n).cwiseAbs().sum();
	else
		return make_vector(x, *n, std::abs(*incx)).cwiseAbs().sum();
}

int
EIGEN_CAT(i, EIGEN_BLAS_FUNC(amax))(int* n, RealScalar* px, int* incx)
{
	if (*n <= 0)
		return 0;
	Scalar* x = reinterpret_cast<Scalar*>(px);

	DenseIndex ret;
	if (*incx == 1)
		make_vector(x, *n).cwiseAbs().maxCoeff(&ret);
	else
		make_vector(x, *n, std::abs(*incx)).cwiseAbs().maxCoeff(&ret);
	return int(ret) + 1;
}

int
EIGEN_CAT(i, EIGEN_BLAS_FUNC(amin))(int* n, RealScalar* px, int* incx)
{
	if (*n <= 0)
		return 0;
	Scalar* x = reinterpret_cast<Scalar*>(px);

	DenseIndex ret;
	if (*incx == 1)
		make_vector(x, *n).cwiseAbs().minCoeff(&ret);
	else
		make_vector(x, *n, std::abs(*incx)).cwiseAbs().minCoeff(&ret);
	return int(ret) + 1;
}

// computes a vector-vector dot product.
Scalar
EIGEN_BLAS_FUNC(dot)(int* n, RealScalar* px, int* incx, RealScalar* py, int* incy)
{
	//   std::cerr << "_dot " << *n << " " << *incx << " " << *incy << "\n";

	if (*n <= 0)
		return 0;

	Scalar* x = reinterpret_cast<Scalar*>(px);
	Scalar* y = reinterpret_cast<Scalar*>(py);

	if (*incx == 1 && *incy == 1)
		return (make_vector(x, *n).cwiseProduct(make_vector(y, *n))).sum();
	else if (*incx > 0 && *incy > 0)
		return (make_vector(x, *n, *incx).cwiseProduct(make_vector(y, *n, *incy))).sum();
	else if (*incx < 0 && *incy > 0)
		return (make_vector(x, *n, -*incx).reverse().cwiseProduct(make_vector(y, *n, *incy))).sum();
	else if (*incx > 0 && *incy < 0)
		return (make_vector(x, *n, *incx).cwiseProduct(make_vector(y, *n, -*incy).reverse())).sum();
	else if (*incx < 0 && *incy < 0)
		return (make_vector(x, *n, -*incx).reverse().cwiseProduct(make_vector(y, *n, -*incy).reverse())).sum();
	else
		return 0;
}

// computes the Euclidean norm of a vector.
// FIXME
Scalar
EIGEN_BLAS_FUNC(nrm2)(int* n, RealScalar* px, int* incx)
{
	//   std::cerr << "_nrm2 " << *n << " " << *incx << "\n";
	if (*n <= 0)
		return 0;

	Scalar* x = reinterpret_cast<Scalar*>(px);

	if (*incx == 1)
		return make_vector(x, *n).stableNorm();
	else
		return make_vector(x, *n, std::abs(*incx)).stableNorm();
}

int
EIGEN_BLAS_FUNC(rot)(int* n, RealScalar* px, int* incx, RealScalar* py, int* incy, RealScalar* pc, RealScalar* ps)
{
	//   std::cerr << "_rot " << *n << " " << *incx << " " << *incy << "\n";
	if (*n <= 0)
		return 0;

	Scalar* x = reinterpret_cast<Scalar*>(px);
	Scalar* y = reinterpret_cast<Scalar*>(py);
	Scalar c = *reinterpret_cast<Scalar*>(pc);
	Scalar s = *reinterpret_cast<Scalar*>(ps);

	StridedVectorType vx(make_vector(x, *n, std::abs(*incx)));
	StridedVectorType vy(make_vector(y, *n, std::abs(*incy)));

	Reverse<StridedVectorType> rvx(vx);
	Reverse<StridedVectorType> rvy(vy);

	if (*incx < 0 && *incy > 0)
		internal::apply_rotation_in_the_plane(rvx, vy, JacobiRotation<Scalar>(c, s));
	else if (*incx > 0 && *incy < 0)
		internal::apply_rotation_in_the_plane(vx, rvy, JacobiRotation<Scalar>(c, s));
	else
		internal::apply_rotation_in_the_plane(vx, vy, JacobiRotation<Scalar>(c, s));

	return 0;
}

/*
// performs rotation of points in the modified plane.
int EIGEN_BLAS_FUNC(rotm)(int *n, RealScalar *px, int *incx, RealScalar *py, int *incy, RealScalar *param)
{
  Scalar* x = reinterpret_cast<Scalar*>(px);
  Scalar* y = reinterpret_cast<Scalar*>(py);

  // TODO

  return 0;
}

// computes the modified parameters for a Givens rotation.
int EIGEN_BLAS_FUNC(rotmg)(RealScalar *d1, RealScalar *d2, RealScalar *x1, RealScalar *x2, RealScalar *param)
{
  // TODO

  return 0;
}
*/
